X-ray tube



Sept. 19, 1933. G. B. JONAS 1,927,456

X-RAY TUBE Filed Nov. 24, 1930 Patented Sept. 19, 1933 STATES X-RAY TUBE Gottfried Bruno Jonas, Eindhoven, Netherlands,

assignor to N. V. Philips Gloeilampenfabrieken, Eindhoven, Netherlands Application November 24, 1930, Serial No.

497,859, and in the Netherlands January 16,

8 Claims. -(Cl. 250-) The present invention relates to X-ray tubes comprising an anode in which the surface struck by cathode rays is provided with seams.

After an X-ray tube has been operated for 5 some time the active surface of the anode will usually be found to be more or less damaged. The surface shows fissures and finally it begins to scale off, which leads to the tube becoming unfit for use.

This drawback is obviated by the invention. The presence of seams in the active surface of the anode appears to counteract the cause of the said harmful effect: the scaling off of the anode is prevented,v or at any rate strongly diminished, by the application of the invention.

The observed favourable effect of the seams is strongest if with an anode whose activesurface is constituted by a layer of a metal of high melting point, for example of tungsten, which is secured to an under layer of a metal of lower melting point such as copper, the seams penetrate into the said underlayer.

The walls of these seams should preferably be in contact with one another in order to avoid as much as possible the harmful effect produced by the penetration of the cathode rays into the seams and to prevent these rays from causing irregularities in the anode target;

The favourable effect of the seams must probably be ascribed to the fact that the strains pro duced in the material due to heating are neutralized for the greater part by them. 7

In order that the invention may be, more readily understood and carried into effect, the invention will be explained more fully with reference to the accompanying drawing which repre-. sents two projections of part of an anode of an X-ray tube.

Figure .1 represents an elevation of the front face of an anode to which during operation in an X-ray tube a rotatory motion is imparted and with which consequentlythe focal spot moves over the active surface. More particularly with X-ray tubes comprising such an anode the invention has proved to be very useful.

Figure 2 represents a section through the front part of the said anode.

The part 1 of the anode consists of a metal having good heat conductivity such, for example, as copper. On this metal part is provided a layer of tungsten in the'shape of a ring 2 which is in satisfactory thermal contact with the underlayer in order to facilitate a rapid dissipation of the heat produced in the surface by the cathode rays striking thereon.

In this tungsten ring are provided in mutually perpendicular directions incisions 3 which penetrate into the copper as is distinctly visible from Figure 2, in which the right-hand half is intended to be a section through such an incision. The walls of these incisions are pressed towards one another and the surface may be worked in' such manner that from the outside the incisions are hardly perceptible or even invisible.

It is evidently not necessary that if incisions in different directions are utilized, they should out each other at right angles.

I claim:

1. An X-ray tube in which the anticathode con sists of a layer of refractory metal constituting the active surface and a backing secured to said layer, said anticathode being provided with seams extending through said layer and into said backmg.

2. An anode for an X-ray tube comprising a portion of metal of high heat conductivity and a target therein of refractory metal, the exposed op erative surface of the target being subdivided by incisions or grooves into a plurality of substantially co-planar areas.

3. An anode for an ;Xray tube comprising a disc of refractory metal'and a body of good heat conductive metal engaging one of the sides there of and in good thermal contact therewith, said disc being subdivided by narrow incisions extending through the thickness of the disc.

4. An anode for an X-ray tube consisting of a body of good heat conductive metal and an insert of refractory metal, said insert taking the form of a tessellated layer of the same metal throughout its entire area, the sides of the elements of this layer contacting with each other.

5. An anode for an X-ray tube consisting for the greater part of a copper body, and a tungsten insert in said body at its operative end, said insert having an exposed active surface divided by a network of narrow substantially closed seams.

6. An anticathode for an X-ray tube having an exposed radiating surface subdivided by seams extending inwardly from the surface for a substantial depth.

7. An anticathode for an X-ray tube having an exposed radiating surface subdivided by seams of substantial depth into separate areas, said areas being in abutting relation at said surface.

8. An X-ray tube having an electrode body provided with an exposed active surface, said body having seams extending from the active surface into said body.

GOTTFRIED BRUNO JONAS. 

